Cranial implant

Abstract

Implantable medical devices (IMD) configured for implantation within a recess formed in a cranium of a patient, as well as associated methods, are described. In some embodiments, the IMD includes a top external surface and another adjacent external surface, e.g., a side surface, which are oriented with respect to each other to define an acute angle. A connection module for an electrical lead or catheter may be included on the top external surface. Embodiments of the invention may facilitate implantation of an IMD within a recess formed in the cranium of a patient at a location remote to an incision made in the scalp of the patient.

The invention claimed is: 
     
       1. An implantable medical device configured to at least one of deliver therapy to or monitor a patient, and configured for implantation within a recess formed in a cranium of the patient, the implantable medical device comprising:
 a top external surface located distally relative to a brain of the patient when the implantable medical device is implanted within the recess; 
 a side external surface adjacent to the top external surface and located proximate to the brain relative to the top external surface when the implantable medical device is implanted within the recess, 
 wherein the side external surface is configured to contact the cranium of the patient within the recess and not contact an external surface of the cranium, when the implantable medical device is implanted within the recess, 
 wherein the side external surface and the top external surface are oriented to define an internal acute angle at a corner of the implantable medical device between the top external surface and the side external surface, 
 wherein the corner of the implantable medical device between the top external surface and the side external surface is adjacent the recess formed in the cranium of the patient when the implantable medical device is implanted within the recess; 
 a bottom external surface that is adjacent to the side external surface and non-adjacent to the top external surface, wherein the side external surface and the bottom external surface are oriented to define an internal obtuse angle, wherein the bottom external surface is oriented to face a brain of the patient, when the implantable medical device is implanted within the recess; 
 a housing that forms a substantially sealed enclosure, wherein the housing includes at least part of the top external surface; 
 a stimulation engine within the substantially sealed enclosure; and 
 a connection module coupled to the housing on the top external surface, wherein the connection module is configured to receive at least one of a lead or a catheter, and the implantable medical device is configured to at least one of deliver therapy to or monitor the patient via the lead or catheter. 
 
     
     
       2. The implantable medical device of  claim 1 ,
 wherein the side external surface converges with the top external surface to define an edge, 
 wherein the edge substantially circumscribes the top external surface. 
 
     
     
       3. The implantable medical device of  claim 1 , wherein the housing includes at least part of the side external surface. 
     
     
       4. The implantable medical device of  claim 1 , wherein the connection module receives the lead or catheter in a direction that is substantially parallel to the top external surface. 
     
     
       5. The implantable medical device of  claim 1 , wherein the housing includes the top external surface and the side external surface. 
     
     
       6. The implantable medical device of  claim 1 , further comprising a member that at least partially encapsulates the housing, wherein the member comprises at least part of at least one of the top external surface and the side external surface. 
     
     
       7. The implantable medical device of  claim 1 , wherein the acute angle is less than approximately 65 degrees. 
     
     
       8. The implantable medical device of  claim 1 , wherein the implantable medical device comprises a neurostimulator. 
     
     
       9. The implantable medical device of  claim 1 , further comprising:
 therapy delivery circuitry within the substantially sealed enclosure; and 
 a processor within the substantially sealed enclosure that controls the therapy delivery circuitry to deliver therapy to the patient. 
 
     
     
       10. The implantable medical device of  claim 1 , wherein the bottom external surface converges with the side external surface to define a second edge that substantially circumscribes the bottom external surface. 
     
     
       11. The implantable medical device of  claim 1 , wherein the side external surface substantially defines a frustum of a cone. 
     
     
       12. The implantable medical device of  claim 1 , further comprising:
 therapy delivery circuitry within the substantially sealed enclosure; and 
 hermetic feedthroughs formed through the top external surface, wherein the hermetic feedthroughs provide electrical connections between electrical contacts of the connection module and the therapy delivery circuitry. 
 
     
     
       13. The implantable medical device of  claim 1 , further comprising a battery within the substantially sealed enclosure formed by the housing. 
     
     
       14. An assembly comprising:
 an implantable medical device configured to at least one of deliver therapy to or monitor a patient, and configured for implantation within a recess formed in a cranium of the patient, wherein the implantable medical device includes:
 a top external surface located distally relative to a brain of the patient when the implantable medical device is implanted within the recess; 
 a side external surface adjacent to the top external surface and located proximate to the brain relative to the top external surface when the implantable medical device is implanted within the recess, 
 wherein the side external surface is configured to contact the cranium of the patient within the recess and not contact an external surface of the cranium, when the implantable medical device is implanted within the recess, 
 wherein the side external surface and the top external surface are oriented to define an internal acute angle at a corner of the implantable medical device between the top external surface and the side external surface, 
 wherein the corner of the implantable medical device between the top external surface and the side external surface is adjacent the recess formed in the cranium of the patient when the implantable medical device is implanted within the recess; 
 a bottom external surface that is adjacent to the side external surface and non-adjacent to the top external surface, wherein the side external surface and the bottom external surface are oriented to define an internal obtuse angle, wherein the bottom external surface is oriented to face a brain of the patient, when the implantable medical device is implanted within the recess; 
 a housing that forms a substantially sealed enclosure, wherein the housing includes at least part of the top external surface; 
 a stimulation engine within the substantially sealed enclosure; and 
 a connection module coupled to the housing on the top external surface, wherein the connection module is configured to receive at least one of a lead or a catheter, and the implantable medical device is configured to at least one of deliver therapy to or monitor the patient via the lead or catheter; and 
 
 a lead coupled to the connection module, wherein the lead includes a plurality of electrodes configured to contact a patient tissue to at least one of deliver therapy to or monitor the patient. 
 
     
     
       15. The assembly of  claim 14 ,
 wherein the side external surface converges with the top external surface to define an edge, 
 wherein the edge substantially circumscribes the top external surface. 
 
     
     
       16. The assembly of  claim 14 , wherein the housing includes at least part of the side external surface. 
     
     
       17. The assembly of  claim 14 , wherein the connection module receives the lead or catheter in a direction that is substantially parallel to the top external surface. 
     
     
       18. The assembly of  claim 14 , wherein the housing includes the top external surface and the side external surface. 
     
     
       19. The assembly of  claim 14 , further comprising a member that at least partially encapsulates the housing, wherein the member comprises at least part of at least one of the top external surface and the side external surface. 
     
     
       20. The assembly of  claim 14 , wherein the acute angle is less than approximately 65 degrees. 
     
     
       21. The assembly of  claim 14 , wherein the implantable medical device comprises a neurostimulator. 
     
     
       22. The assembly of  claim 14 , further comprising:
 therapy delivery circuitry within the substantially sealed enclosure; and 
 a processor within the substantially sealed enclosure that controls the therapy delivery circuitry to deliver therapy to the patient. 
 
     
     
       23. The assembly of  claim 14 , wherein the bottom external surface converges with the side external surface to define a second edge that substantially circumscribes the bottom external surface. 
     
     
       24. The assembly of  claim 14 , wherein the side external surface substantially defines a frustum of a cone. 
     
     
       25. The assembly of  claim 14 , further comprising:
 therapy delivery circuitry within the substantially sealed enclosure; and 
 hermetic feedthroughs formed through the top external surface, wherein the hermetic feedthroughs provide electrical connections between electrical contacts of the connection module and the therapy delivery circuitry. 
 
     
     
       26. The assembly of  claim 14 , wherein a profile of a cross-section of the implantable medical device that bisects both the top external surface and the bottom external surface and intersects the side external surface defines a convex polygon. 
     
     
       27. The assembly of  claim 14 , wherein the top surface is a convex top surface. 
     
     
       28. The assembly of  claim 27 , wherein the bottom surface is a concave bottom surface. 
     
     
       29. An implantable medical device configured to at least one of deliver therapy to or monitor a patient, and configured for implantation within a recess formed in a cranium of the patient, the implantable medical device comprising:
 a top external surface located distally relative to a brain of the patient when the implantable medical device is implanted within the recess; 
 a side external surface adjacent to the top external surface and located proximate to the brain relative to the top external surface when the implantable medical device is implanted within the recess, 
 wherein the side external surface is configured to contact the cranium of the patient within the recess and not contact an external surface of the cranium, when the implantable medical device is implanted within the recess, 
 wherein the side external surface and the top external surface are oriented to define an internal acute angle, 
 wherein a corner of the implantable medical device between the top external surface and the side external surface is adjacent the recess formed in the cranium of the patient when the implantable medical device is implanted within the recess; 
 a bottom external surface that is adjacent to the side external surface and non-adjacent to the top external surface, wherein the side external surface and the bottom external surface are oriented to define an internal obtuse angle, wherein the bottom external surface is oriented to face a brain of the patient, when the implantable medical device is implanted within the recess; 
 a housing that forms a substantially sealed enclosure, wherein the housing includes at least part of the top external surface; 
 a stimulation engine within the substantially sealed enclosure; and 
 a connection module coupled to the housing on the top external surface, wherein the connection module is configured to receive at least one of a lead or a catheter, and the implantable medical device is configured to at least one of deliver therapy to or monitor the patient via the lead or catheter, 
 wherein a profile of a cross-section of the implantable medical device that bisects both the top external surface and the bottom external surface and intersects the side external surface defines a convex polygon.